Question

If 20 mL of 0.01 M aqueous HCl is required to neutralize 30 mL of an aqueous solution of NaOH, determine the molarity of the NaOH solution.


==> I got 0.01 M NaOH as my answer. Is this correct?

Answer 1

No, it isn't correct although I suspect you worked it correctly. I suspect you simply read your calculator incorrectly.
mL x M = mL x M (you can use this simplified expression since the reaction is 1:1 and ONLY then).
20 x 0.01 = 30 x M
M = (20*0.01)/30 = 0.00667 which rounds to 0.0067 M.
If your calculator is like most, you have it set to read to two places, so the calculator rounds 0.006 to 0.01.

Answer 2

Ohhh I see. This makes more sense. Thank you! :)